Herpex simplex virus 1 (HSV-1) RNA labeled with with [methyl-3H] methionine at various times during the infectious cycle and purified by hybridization to viral DNA was analyzed for the presence of methylated nucleotides. The data indicate the following. (i) RNA labeled from 0 to 14 h postinfection and accumulating in the cytoplasm contained internal base-methylated nucleotides and terminal oligonucleotides consistent with the structure 7mG(5')ppp-(5')XmpYmpNp. Similar methylated nucleotides and oligonucleotides were also found in viral RNA accumulating in the cytoplasm of cells treated with cycloheximide from the time of infection. Previous studies (M. Kozak and B. Roizman, 1974) have shown that, whereas the RNA accumulating in the 14-h infected cells contains all of the sequences functioning as mRNA throughout infection, the RNA accumulating in the cytoplasm of cycloheximide-treated cells is associated with polyribosomes synthesizing the earliest (alpha) group of polypeptides specified by the virus. (ii) Cytoplasmic viral RNA from cells labeled 11 to 14 h postinfection as well as the total adenylated RNA in the cytoplasm and polyribosomes labeled in the same fashion contained the terminal oligonucleotide but not the internal base-methylated nucleotide.

No abstract

No abstract

In the cytoplasm of eucaryotic cells, mRNA is associated with proteins. These mRNA-protein complexes, termed messenger ribonucleoprotein (mRNP) particles, are divided into two functional classes. The first class contains free (nonribosome-associated) mRNPs which have been termed informosomes by others. The second class of mRNPs, those associated with polysomes, are actively

No abstract